OBDunio RPM triggered output

[djarmyssg]

Ok guys, Heres the question, I got my OBDuino running like a champ, But I would like to add another option to it. What im looking to do is to have a menu option where you can set what RPM you would like to select, then when the vehicle hits that RPM it would activate and output on the Arduino that I can use to activate a relay. I also need to make sure the RPM selection can not go below, say, 2500... Any ideas?!?!?!

[blinder]

Anyone? This would be the source code code.google.com/p/opengauge/source/browse/trunk/obduino32K/obduino32K.pde
There would be needed variable of engine's rpm. And this reading would be in loop() function thats right?